A.K.
I also have a 3 year old who needs constant entertainment.
There are always tons of things she could do with them. Some more common than others:
1. Coloring, finger painting, & water colors. Even the 1 year old could do all of these. There are finger paints out there that are washable when they get it on their clothing. Now that it's getting warmer, you could just strip them down to their undies and let them at it.
2. Forts in the house. We make the indoor fort together and I give her a flashlight and she plays in there for hours.
3. Play dough. If she's feeling up to it she could make her own. Which is always a fun project for any kid to be involved in the making and cooking of something. There are tons of recipes for homemade playdough online.
4. Let them play in the sink. Anything to do with water is very entertaining for them.
Most all of these that I mentioned she could do with her kids. She could paint, color, play with playdough, make forts.
Hope this helps her!
A.